Time delay cord cutter



Sept. 26, 1961 c. P. CAIRELLI 3,001,235

TIME DELAY CORD CUTTER Filed Sept. 4, 1958 2 Sheets-Sheet 1 FIG. I

FIG. 2

IN V EN TOR. CARMEN P. CAIRELLI 2 TORNEYS Sept. 26, 1961 c. P. CAIRELLI 3,001,285

' TIME DELAY CORD CUTTER Filed Sept. 4, 1958 2 Sheets-Sheet :2

INVENTOR. CARMEN P. CAIRELLI I. ATTORNEYS Patented Sept. 26, 1961 Ware Filed Sept. 4,1958, Ser. No. 758,943 6 Claims. (Cl. 30-127) This invention generally relates to cord cutters operable after a predetermined time delay and relates more specifically to rotary cord cutters which impart an improved slicing action to the cutting edge.

The reliability of a cord cutter is determined in a large part by the nature of the cutting action performed. For example, cutters which attempt to shear the cordoften expend their energy overcoming the natural elasticity of the cord without actually severing the cord, and such cutters most often expend their cutting force instantaneously. Such cutters have required exceptionally heavy and powerful mechanisms as well as complicated cordholding fixtures to make them at all reliable.

It is therefore an object of this invention to provide a rotary cord cutter utilizing an improved slicing action to overcome cord resiliency and effect reliable severing of the cord.

It is a further object of this invention to provide a time delay rotary cord cutter which is small, rugged, sufficiently reliable for military and scientific use and sufliclently inexpensive to manufacture so that it can be considered expendable after a single use.

It is a still further object of this invention to provide a rotary cord cutter utilizing slicing action whose operation is effective after the lapse of a predetermined time and whose timing mechanism operates without load during the timed interval.

These and other objects and features of the invention will be in part obvious and in part pointed'out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a top view of a preferred embodiment of the invention with the top cover removed;

FIG. 2 is a partially cutaway side elevation of the invention;

FIG. 3 is a reduced-size top view of the embodiment of FIG. 1 with the top cover in place;

FIGS. 4 and 5 are partial top views of the mechanism of the preferred embodiment in different stages of its operation.

Referring now to FIGS. 1, 2 and 3, it is seen that the preferred embodiment of my invention includes a generally cylindrical outer casing having a bottom 1 with integral side walls and a cover 2 secured to bottom 1 by a plurality of bent-over tabs 3. Shaft 4, supported within the mechanism as will be subsequently described, extends through aperture 5 in cover 2 and carries mechanism winding lever 6 adjacent its outer end. Winding lever 6 is provided with a central slot which engages opposed fiat sides 7 on shaft 4 whose end is threaded to receive nut 8 thereby to retain winding lever 6 in position.

Referring particularly to FIG. 2, it is seen that plate 10 is supported by and aflixed to container 1 by threaded fasteners 11 and that plate 12 is supported relative to plate 10 by a plurality of studs 13. Plates 10 and 12 and studs 13 define a frame in which shaft 4 is journaled for rotation under the driving force of spring 14. Gear 15 is secured to shaft 4 and has a portion of its teeth removed (see FIG. 1) and is therefore termed a mutilated States Patent Ofitice gear. The teeth of mutilated gear 15 engage pinion 16 whose rotation is controlled by the gear train including gears 17, 18, 19 and 20 which are supported respectively on shafts 21, 22 and 23 that are journaled for rotation in plates .10 and 12. Shaft 23 also supports escape wheel 24 whose rate of rotation is controlled by pallet 25, whose pallet pins 26 and 27 alternately engage the toothed periphery of escape wheel 24.

The mechanism as thus far described is essentially a clock-like mechanism whose spring 14 is wound by rotating winding lever 6 in a counter-clockwise direction and Whose rate of unwinding (and therefore main shaft rotation) is controlled by the gear train and escapement mechanism; It is noted, at this point, that escape wheel 24 is provided with a plurality of circumferential spaced apertures 28, any one of which is engageable by locking pin 29 inserted through aligned apertures in cover 2, plates 10 and 12, and bottom member 1. Thus, the spring can be wound and locked in the wound position by the insertion of locking pin 29to prevent rotation of escapement wheel 24.

Drive plate or carrier 31 is supported by cylindrical portion 30 of shaft 4 and is provided with an elongated central slot 32 whose side walls engage opposed flat sides on shaft 4 to establish driving engagement therewith. Spring 33 has one end engaging bent-up tab 34 on drive plate 31 and its other end embracing a peripheral slot on shaft 4 to retain drive plate 31 on shaft 4 and to bias drive plate 31 into the position shown in FIG. 1, in which shaft 4 is. positioned in the upper end of slot 32. Knife blade 35 is secured to drive plate 31 by rivets 36 in a position so that the cutting edge 37 extends beyond the outer periphery of drive plate 31 and defines an acute angle with a'radius of plate 31 parallel to slot 32. This angle is designated A in FIG. 5. 3

Registering apertures in cover 2, plates 10' and 12, and bottom 1 are provided With grommets 38 and define guide means for cord 39 shown in dotted lines in FIG. 2.

Assuming spring 14 has been wound by rotatingwinding lever 6 in a clockwise direction and that locking pin 29 is in place, it is seen, by referring to FIGS. 2, 4 and 5, that removal of pin 29 allows spring 14 to rotate shaft 4 (and therefore drive plate 31) in a counterclockwise direction so as to move cutting edge 37 of knife blade 35 toward cord 39. However, contact is not established until after drive plate 31 has been released for uncon trolled rotation by the mutilated portion of mutilated gear 15. As cutting edge 37 contacts cord 39, it exerts a compressive force tending to shear cord 39. However, since cutting edge 37 is mounted at an angle to the radius of plate 31 parallel to slot 32, driving contact between cutting edge 37 and cord 39 produces a reaction force having a vectorial component along the aforementioned radius of plate 31. When the radial vectorial component exceeds the force of spring 33, drive plate 31 will slide on shaft 4 thereby sliding cutting edge 37 relative to cord 39 to produce a slicing action. FIG. 5 shows drive plate 31 when it has been radially displaced against spring 33. This slicing action overcomes natural cord resiliency and produces the improved cord severing action obtained in accordance with applicants invention.

It is therefore seen that a cord cutter is provided with a time delay rotary actuator in which no load is placed on the time delay mechanism during the timing cycle and which effectively utilizes slicing action to reliably sever a length of cord. As is apparent from its construction, the cord cutter of this invention is sufficiently economical to construct as to be expendable after a single use while, at the same time, providing reliable timing and cord cutting functions of the degree sufiicient for military and scientific use.

As variations could be made in the above construction and the different embodiments of this invention could be made by one skilled in the art, such variations are intended to be included within the scope of this invention.

I claim:

1. A time delay rotary cord cutter comprising a frame, a shaft journaled for rotation in said frame, a spring operatively connected to said shaft to impart rotation thereto, a cutting edge, means operatively connecting said cutting edge to said shaft for rotation therewith, including means permitting limited radial movement of said cutting edge toward and away from said shaft, guide means in said frame engageable with a cord to be cut, said guide means positioning the cord for engagement with said cutting edge during rotation thereof and means for controlling the speed of rotation of said shaft by said spring, said means including a mutilated gear secured to said shaft, said mutilated gear having a toothed portion engageable in said means for controlling the speed of rotation of said shaft and a mutilated portion for disengaging said mutilated gear therefrom, whereby the control means is rendered inoperative by the mutilated portion of said gear thereby to release said cutting edge for uncontrolled rotation into engagement with the cord.

2. A time delay rotary cord cutter comprising a frame, a shaft journaled for rotation in said frame, a spring operatively connected between said frame and said shaft to impart rotation to said shaft, an escapement mechanism operatively connected to said shaft to control its rotation, said escapement mechanism being operatively connected to said shaft by a mutilated gear whereby said escapement is disconnected from said shaft by the mutilated portion of said mutilated gear, a drive plate, a cutter secured to and having its cutting edge extending beyond the outer periphery of said drive plate, and means interconnecting said drive plate and said shaft whereby said drive plate is rotated by said shaft, said means permitting limited radial movement of said drive plate and said cutting edge toward and away from said shaft, said cutter having its cutting edge mounted at an acute angle relative to a radius of said drive plate parallel to the direction of radial movement of said drive plate whereby contact of said cutting edge with the cord will initiate limited radial movement of said cutting edge towards said shaft.

3. A time delay rotary cord cutter comprising a frame, a shaft journaled for rotation within said frame, said shaft having a pair of opposed flat sides formed thereon, a'drive plate mounted on said shaft, a knife blade secured to said drive plate and having a cutting edge extending beyond the periphery of said drive plate, said drive plate having a central slot elongated towards said cutting edge and whose side walls engage the flat sides of said shaft, said knife blade being mounted at an angle to the radius of said drive plate that is parallel to the slot side walls whereby contact of said cutting edge with the cord will initiate limited radial movement of said cutting edge towards said shaft, a spring operative between said frame and said shaft to impart rotation thereto, and means for controlling the speed of rotation of said shaft by said spring, said means being operatively connected to said shaft by a mutilated gear secured to said shaft whereby said control means is rendered inoperative by the mutilated portion of gear thereby to release said knife blade for uncontrolled movement.

4. The time delay rotary cord cutter as set forth in claim 3 wherein a spring operatively interconnects said drive plate and said-shaft to bias one end wall of the drive plate slot in engagement with said shaft thereby to urge said knife blade radially towards the cord to be cut.

5. A time delay rotary cord cutter comprising a frame, a shaft journaled for rotation within said frame, said shaft having opposed flat sides thereon, a drive plate carried by said shaft, a knife blade carried by said drive plate and having a cutting edge extending beyond the periphery thereof, said drive plate having an elongated central slot extending towards the cutting edge and having parallel side walls engaging the flat sides of said shaft, a spring operative between said shaft and said drive plate to bias said drive plate into one slot extremity, the cutting edge of said knife blade defining an acute angle with the sides of the slot in the drive plate whereby contact of said cutting edge with the cord will initiate limited radial movement of said cutting edge towards said shaft, guide means in said frame engageable with the cord to be cut, said guide means serving to position the cord for engagement with the knife blade, a spring operatively connected between said frame and said shaft for imparting rotation to said shaft, and escapement means including a mutilated gear secured to said shaft for controlling the rotative speed thereof, said mutilated gear haw'ng a toothed portion engageable in said escapement means for controlling the rotation of said shaft and a mutilated portion for disengaging said mutilated gear therefrom, the mutilated portion of said mutilated gear serving to render the escapement inoperative to release said cutting edge for uncontrolledirotation into engagement with the cord.

6. In a time delay cord cutter, cord cutting means comprising a drive plate, a knife blade mounted at the outer periphery of said drive plate and having its cutting edge extending therebeyond, the cutting edge of said knife blade being outwardly inclined to a radius of said drive plate, a shaft, means supporting said drive plate on said shaft for rotation therewith, said means permitting limited radial movement of said drive plate relative to said shaft along the aforementioned radius, and spring means acting upon said drive plate and urging said knife blade away from said shaft, said means for supporting said drive plate on said shaft including a slot having parallel side walls formed in said drive plate and a pair of opposed flat sides formed on said shaft and engaging the side walls of said slot.

References Cited in the file of this patent UNITED STATES PATENTS 533,208 Campbell Jan. 29, 1895 t 628,908 Lewis July 11, 1899 931,791 Niergarth Aug. 24, 1909, 1,318,320 Frohn Oct. 7, 1919 

